• KSCE Journal of Civil and Environmental Engineering Research
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• 제29권1A호
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• pp.31-43
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• 2009

In this study, the numerical method is presented, which can consider the various train types and can solve the equations of motion for a vehicle-bridge interaction analysis by non-iteration procedure through formulating the coupled equations of motion. The coupled equations of motion for the vehicle-bridge interaction are solved by the Newmark ${\beta}$ of a direct integration method, and by composing the effective stiffness matrix and the effective force vector according to a analysis step, those can be solved with the same manner of the solving procedure of equilibrium equations in static analysis. Also, the effective stiffness matrix is reconstructed by the Skyline method for increasing the analysis effectiveness. The Cholesky's matrix decomposition scheme is applied to the analysis procedure for minimizing the numerical errors that can be generated in directly calculating the inverse matrix. The equations of motion for the conventional trains are derived, and the numerical models of the conventional trains are idealized by a set of linear springs and dashpots with 16 degrees of freedom. The bridge models are simplified by the 3 dimensional space frame element which is based on the Euler-Bernoulli theory. The rail irregularities of vertical and lateral directions are generated by the PSD functions of the Federal Railroad Administration (FRA). The results of the vehicle-bridge interaction analysis are verified by the experimental results for the railway plate girder bridges of a span length with 12 m, 18 m, and the experimental and analytical data are applied to the low pass filtering scheme, and the basis frequency of the filtering is a 2 times of the 1st fundamental frequency of a bridge bending.

• Anxiety and mood
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• 제6권1호
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• pp.45-54
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• 2010

Objective : This study aimed to investigate and compare the prevalence of depression and suicidality among the elderly in a rural city according to their residence type. Methods : Participants were 311 elderly people (109 male and 202 female) in Icheon City, whom trained researchers interviewed and examined Geriatric Depression Scale, Social Support Scale, Instrumental Activities of Daily Living, Activities of Daily Living, Quality of Life Scale, and Mini International Neuropsychiatric Interview (MINI), module C. Using these data, we analyzed participants' risk factors associated with depression and suicidality. Results : The prevalence of depression was 28.0%. The prevalence in the elderly living alone and those admitted to residential facilities was significantly higher than that among the elderly living with family. Suicidality frequency was 19.6%. The suicidality frequency among the elderly living alone and those admitted to facilities was significantly higher than that among the elderly living with family. The risk factors for depression were age, admission to a facility, and low economic status. The suicidality risk factors were living alone, admission to a facility, poor social support, and a history of headache. Conclusion : These results showed the prevalence of depression and frequency of suicidality among the elderly in such a city was quite high. The results of this study remind psychiatrists of the importance of early detection and therapeutic intervention for the elderly with a high risk of depression and suicidality.

• Journal of Intelligence and Information Systems
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• 제26권1호
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• pp.97-117
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• 2020

Product evaluation criteria is an indicator describing attributes or values of products, which enable users or manufacturers measure and understand the products. When companies analyze their products or compare them with competitors, appropriate criteria must be selected for objective evaluation. The criteria should show the features of products that consumers considered when they purchased, used and evaluated the products. However, current evaluation criteria do not reflect different consumers' opinion from product to product. Previous studies tried to used online reviews from e-commerce sites that reflect consumer opinions to extract the features and topics of products and use them as evaluation criteria. However, there is still a limit that they produce irrelevant criteria to products due to extracted or improper words are not refined. To overcome this limitation, this research suggests LDA-k-NN model which extracts possible criteria words from online reviews by using LDA and refines them with k-nearest neighbor. Proposed approach starts with preparation phase, which is constructed with 6 steps. At first, it collects review data from e-commerce websites. Most e-commerce websites classify their selling items by high-level, middle-level, and low-level categories. Review data for preparation phase are gathered from each middle-level category and collapsed later, which is to present single high-level category. Next, nouns, adjectives, adverbs, and verbs are extracted from reviews by getting part of speech information using morpheme analysis module. After preprocessing, words per each topic from review are shown with LDA and only nouns in topic words are chosen as potential words for criteria. Then, words are tagged based on possibility of criteria for each middle-level category. Next, every tagged word is vectorized by pre-trained word embedding model. Finally, k-nearest neighbor case-based approach is used to classify each word with tags. After setting up preparation phase, criteria extraction phase is conducted with low-level categories. This phase starts with crawling reviews in the corresponding low-level category. Same preprocessing as preparation phase is conducted using morpheme analysis module and LDA. Possible criteria words are extracted by getting nouns from the data and vectorized by pre-trained word embedding model. Finally, evaluation criteria are extracted by refining possible criteria words using k-nearest neighbor approach and reference proportion of each word in the words set. To evaluate the performance of the proposed model, an experiment was conducted with review on '11st', one of the biggest e-commerce companies in Korea. Review data were from 'Electronics/Digital' section, one of high-level categories in 11st. For performance evaluation of suggested model, three other models were used for comparing with the suggested model; actual criteria of 11st, a model that extracts nouns by morpheme analysis module and refines them according to word frequency, and a model that extracts nouns from LDA topics and refines them by word frequency. The performance evaluation was set to predict evaluation criteria of 10 low-level categories with the suggested model and 3 models above. Criteria words extracted from each model were combined into a single words set and it was used for survey questionnaires. In the survey, respondents chose every item they consider as appropriate criteria for each category. Each model got its score when chosen words were extracted from that model. The suggested model had higher scores than other models in 8 out of 10 low-level categories. By conducting paired t-tests on scores of each model, we confirmed that the suggested model shows better performance in 26 tests out of 30. In addition, the suggested model was the best model in terms of accuracy. This research proposes evaluation criteria extracting method that combines topic extraction using LDA and refinement with k-nearest neighbor approach. This method overcomes the limits of previous dictionary-based models and frequency-based refinement models. This study can contribute to improve review analysis for deriving business insights in e-commerce market.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• 제28권1호
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• pp.111-126
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• 1998

In this study, radiographic evaluation was made using panoramic radiography and cross-sectional tomography of SCANORA/sup (R)/ in male and female adults in their 20's on the relationship between the maxillary sinus floor and the apex of the maxillary molar, to test the accuracy and effectiveness of the cross-sectional tomography, and to use this information in the assessment of preop. and postop. root canal treatment, apical surgery, extraction and implantology. Forty-one adults with an average age of 24.4 years were studied using panoramic radiography and cross-sectional tomography. In panoramic view and cross-sectional view, the position of the apices of maxillary molars were classified as separated, contacted, or protruded type; the general shape of the maxillary sinus floor was evaluated horizontally and vertically from cross-sectional tomography. The accuracy of each radiography was tested using maxilla from 5 fresh cadavers from the Anatomy Lab at Yonsei University Dental College, and panoramic view and cross-sectional tomography were taken in the same condition as with the patients. The results were as follows: 1. Panoramic view and cross-sectional view were taken in the maxilla specimen, and the actual distance between the maxillary sinus floor and the tooth apices were measured in the specimen; the median values of the distance from the tooth apices to the maxillary sinus floor in the panoramic view, cross-sectional view and in the actual maxilla specimen were 2.83 mm, 4.51mm, and 4.l5mm, respectively. In the cross-sectional view, the measured distance was close to the actual distance but in the panoramic view, the measured distance was far from the actual distance. 2. When the results of the panoramic view and cross-sectional view were compared, 40.5％ of the results agreed with each other in the two radiographic methods and buccal roots of the 2nd molar were the closest to the maxillary sinus floor in the cross-sectional tomography. 3. In cross-sectional view, when the vertical relationship of the maxillary sinus floor and maxillary roots was assessed, in 1st molars, type II (the sinus floor that extends down to the buccolingual furcation area) was predominant, while in 2nd molars, type I (the sinus floor located above the level connecting the buccal and lingual apices) was predominant. In the horizontal relationship, in 1st molars, type II (the lowest floor of the maxillary sinus located in between the buccal and lingual roots) was predominant; in 2nd molars, type I (the lowest floor of the maxillary sinus located on the buccal side of the buccal roots) and type II appeared in similar frequency. In conclusion, the SCANORA/sup (R)/ cross-sectional tomography was more effective than the frequently used panoramic view, in that the relationship of the maxillary molars and maxillary sinus floor can be evaluated more accurately and the buccolingual cross-sectional view can also be observed. And maxillary sinus floor that was close to maxillary 2nd molar had tendency to be located on buccal side than that close to 1st molar. Therefore, cross-sectional tomography is an effective and accurate method to evaluate the position of the teeth in relation to the sinus floor preoperative and can be easily used to diagnose localized periapical lesions. Also, the image quality obtained was quite satisfactory.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제16권12호
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• pp.8643-8648
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• 2015

In this paper presents the design and demonstrate 8 W 3-stage HPA(High Power Amplifier) MMIC(Monolithic Microwave Integrated Circuits) for Ka-band down link satellite communications payload system at 19.5 GHz ~ 22 GHz frequency band. The HPA MMIC consist of 3-stage GaN HEMT(Hight Electron Mobility Transistors). The gate periphery of $1^{st}$ stage, $2^{nd}$ stage and output stage is determined $8{\times}50{\times}2$ um, $8{\times}50{\times}4$ um and $8{\times}50{\times}8$ um, respectively. The fabricated HPA MMIC shows size $3,400{\times}3,200um^2$, small signal gain over 29.6 dB, input matching -8.2 dB, output matching -9.7 dB, output power 39.1 dBm and PAE 25.3 % by using 0.15 um GaN technology at 20 V supply voltage in 19.5~22 GHz frequency band. Therefore, this HPA MMIC is believed to be adaptable Ka-band satellite communication payloads down link system.

• Journal of Elementary Mathematics Education in Korea
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• 제9권1호
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• pp.65-84
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• 2005

The purpose of this study was to analyze the contents and designs of the developed 22 teaching and programs for the gifted students in elementary mathematics. The focus of the analysis were the participants and the characteristics of the contents, and were to reflect them on the areas of the 7th elementary mathematics curriculum and Renzulli's Enrichment Triad Model. The results of the study as follows: First, the programs for the low grade gifted students are very few compared to those of the high grade students. For earlier development of the young gifted students, we need to develop more programs for the young gifted students. Second, there are many programs in the area of geometry, whereas few programs are developed in the area of measurement. We need to develop programs in the various areas such as measurement, probability and statistics, and patterns and representations. Third, most programs do not follow the steps of the Renzulli's Enrichment Triad Model, and the frequency of appearance of the steps are the 1st, 2nd, and 3rd enrichments, sequentially. We need to develop hierarchical programs in which the sequency and relations are well orchestrated. Fourth, the frequency of appearance is as follows as sequentially: types of exploration of topics, creative problem solving, using materials, project types, and types of games and puzzles. In the development of structure of the program, the following factors should be considered: name of the chapter, overview of the chapter, objectives, contents by steps, evaluation, reading materials, and extra materials.

• Culinary science and hospitality research
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• 제15권3호
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• pp.1-14
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• 2009

One of the tasks given to the hotel business is to improve ES(Employee Satisfaction) through educational training for enhancing job efficiency and service quality, not product competition. In the current domestic field, however, ES(Employee Satisfaction) based on appropriate educational training hasn't been established yet. The purpose of this study is to verify the effect of educational training including recognizing the necessity of frequency, the level of lecture conscience, motivation, and internalization along with job commitment. The cohort of women(n=128, 44.4%) and men(n=160, 55.6%) was monitored by the questionnaire data from October 13th to 31st, 2007. It was assessed by (1) the recognition of educational training, (2) educational training practices, (3) organizational identification, (4) brand identification, and (5) job commitment. Statistical analysis was conducted using SPSS (Statistical Package for Social Science), data coding, and the data cleaning system. As a result, it was proved that frequency, the level of lecture conscience, motivation, the recognition of necessity are in proportion to brand identification and organization identification. In addition, identification through educational training can raise the efficiency of job commitment.

• Journal of Music and Human Behavior
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• 제13권1호
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• pp.89-110
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• 2016

This study examined the effect of an interactive instrument playing program on the social interaction of adults with autism spectrum disorder (ASD). A single subject design with multiple baselines across participants was applied, and three adults with severe ASD in their late 20s living at a group home participated in this study. Participants received a total of 25 group sessions. During the intervention, participants engaged in structured instrument playing in which initiation and response to socially interactive behaviors were musically cued, and target behaviors were reinforced in the musical environment. At pre- and posttest, the frequency of initiation of and responding to social interaction behaviors were recorded and analyzed. The results of this study showed that the frequency of both initiation of, and response to, social interaction increased for all participants during the intervention phase, compared to the baseline phase. This result demonstrates that interactive instrument playing increased social behaviors of adults with ASD. It also shows that musically delivered social information can facilitate adults with ASD understanding the intention of social partners in social contexts and motivate this population to engage in social interaction.

• Journal of Intelligence and Information Systems
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• 제22권2호
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• pp.115-125
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• 2016

The Bollinger Band indicating the current price position in the recent price action range is obtained by adding/substracting the simple standard deviation (SSD) to/from the simple moving average (SMA). In this paper, we first compare the characteristics of the SMA and the exponential moving average (EMA) in the operator's point of view. A basic equation is obtained between the interval length N of the SMA operator and the weighting factor ${\rho}$ of the EMA operator, that makes the centers of the 1st order momentums of each operator impulse respoinse identical. For equivalent N and ${\rho}$, frequency response examples are obtained and compared by using the discrete time Fourier transform. Based on observation that the SMA operator reacts more excessively than the EMA operator, we propose a novel exponential standard deviation (ESD) band centered at the EMA and derive an auto recursive formula for the proposed ESD band. Practical examples for the ESD band show that it has a smoother bound on the price action range than the Bollinger Band. Comparisons are also made for the gap corrected chart to show the advantageous feature of the ESD band even in the case of gap occurrence. Trading techniques developed for the Bollinger Band can be straight forwardly applied to those for the ESD band.

• Journal of Korean Academy of Nursing Administration
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• 제6권1호
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• pp.31-54
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• 2000

This study was aimed for effective nursing performance of the nurse to be able dedicate to the development of professional nursing work by understanding correlation between the leadership style of head nurse and the nursing performance of the nurse. The materials have been collected through structured questionnaires for 18 days from Feb. 2, 1999 to Feb. 20 from 234 nurses presently working at 4 hospitals Circumstances aptitude theory of Fleishman (1973) were used as the device of measuring leadership style, and staff nurses nursing performance were done by head nurses utilizing questionnaire adopted from Park. Data was analyzed by frequency, mean, ANOVA, ANCOVA, and Pearson's correlation coefficiency by using SPSS program. The results are as follows ; 1. Head nurse leadership was classified in the following manner : duty and human relationships oriented style of head nurse leadership(3.76), human relationship oriented style(3.30), duty leadership oriented style(3.12), and non-interference leadership style(2.77). Duty and human relationships showed highest score in this category. 2. The mean of nursing performance was 3.66, dependent nursing duty was 3.88, interpersonal relationship 3.78, and independent nursing was 3.34. 3. An education course of nursing performance by general characteristics was statistically significant. Job satisfaction, for seen working periods, and motivation for choosing a nursing job of nursing job characteristics was statistically siginficant. 4. As the degree of independence nursing performance increases, the degree and of dependance and interpersonal relationship of nursing performance increases. 5. The relationship between nurse leadership style and nursing performance were statistically different. The degree of duty and human relationship style of the head nurse were highest in dependent and independent nursing performance. Therefore, it is desirable that the head nurse should demonstrate the leadership style high in the duty and human relationships for effective nursing performance.